Fast range-corrected proton dose approximation method using prior dose distribution.

Area of Science:

• Medical Physics
• Radiation Oncology
• Computational Imaging

Background:

• Robust proton therapy requires efficient dose calculation for plan optimization and evaluation under varying conditions.
• Setup errors and anatomical changes necessitate accurate dose distribution assessment.

Purpose of the Study:

• To develop and validate a computationally efficient approximate method for rapid dose calculation in proton therapy.
• To assess the accuracy of this method in accounting for setup errors and anatomical changes.

Main Methods:

• An approximate method was developed to rapidly calculate dose distributions based on a reference dose distribution.
• The method was validated by comparing its results to a commissioned treatment planning system.
• Accuracy was evaluated using 3D gamma index and dose-volume histogram (DVH) deviations for simulated setup errors and anatomical deformations.

Main Results:

• The approximate method achieved high accuracy, with average 3D gamma passing rates of 96% (setup errors) and 89% (anatomy changes) at 3%/3mm criteria.
• Cumulative DVH (cDVH) deviations were low, with average RMS of 0.5% and maximum of 1.5% for setup errors, and 0.6% and 2.7% for anatomical changes.
• The method significantly reduced computation time while maintaining acceptable accuracy.

Conclusions:

• The fast dose approximation method provides an accurate and computationally efficient solution for proton therapy dose calculations.
• This method can effectively handle density variations due to setup and anatomical changes, supporting robust plan optimization and evaluation.